Hi all,
Now that the smoke has cleared a bit from my installation in Ottawa, I'd like to ask about some performance issues with file seeking.
I'm now using mpeg2 (dvd quality or so) encoded videos with single frame GOPs, and seeking them using the table of contents generated by mpeg3toc.
The problem is that two 640x480 videos seeking randomly use up 80% of my new AMD64 3200+. This seems to be a bit of a hog... I also endcoded a test file as "photo-jpeg" in a quicktime container. I could also seek that file, but the CPU usage was about the same - 10%.
I'm reading the files off a dual disk SATA raid0, so the disk access should not be the problem. (I can play 3 DV videos off the same array using mplayer w/out lost frames.)
So the question is:
#1 What is the best video codec for random seeking performance?
#2 How can I profile pd/gem/diskIO/decoding to find out what is causing the largest bottleneck? Suggest tools?
My previous installation used 256x256 photo-jpeg MOVs playing simultaneously on a duron 900 and gem 0.87. These videos were just played and not seeked.
Thanks all! I'd really like to be able to get better performance out of this patch.
.b.
B. Bogart wrote:
Hi all,
Now that the smoke has cleared a bit from my installation in Ottawa, I'd like to ask about some performance issues with file seeking.
I'm now using mpeg2 (dvd quality or so) encoded videos with single frame GOPs, and seeking them using the table of contents generated by mpeg3toc.
The problem is that two 640x480 videos seeking randomly use up 80% of my new AMD64 3200+. This seems to be a bit of a hog... I also endcoded a test file as "photo-jpeg" in a quicktime container. I could also seek that file, but the CPU usage was about the same - 10%.
hi i have had very similar problems when playing back 2 PAL-videos (uncompressed) with a machine similar to yours (although the 2 video files were on spread on two SATA-raids (raid0, 2 disks)
even though the disc-access should not be a problem, it seems like pd/Gem spent most of the time waiting for the 2 raids.
thus i have changed [pix_film] (and [pix_movie]) to access the disc-arrays in a threaded way. this sped up performance significantly.
the changes are in the CVS. you can turn on/off threading with [thread 0/1( to the [pix_film]/[pix_movie]
mfg.ads.r IOhannes
hi,
i was wondering about mac os X ? what is the best codec for mixing (blending, seeking) videos? quicktime for sure, but what codec and size: 720x480 DV or 640x480 with a codec like mpeg4, photojpeg? it's a g4 laptop, with 512 ram.... 50 videos, 2 seconds each.
thank you! pat
On 11/5/05, patrick puredata@11h11.com wrote:
hi,
i was wondering about mac os X ? what is the best codec for mixing (blending, seeking) videos? quicktime for sure, but what codec and size: 720x480 DV or 640x480 with a codec like mpeg4, photojpeg? it's a g4 laptop, with 512 ram.... 50 videos, 2 seconds each.
I get at least 3 NTSC DV clips playing 30 fps at once on a 1 Ghz G4 laptop using the internal drive. A fourth might be possible using a Firewire drive. I hope you aren't trying to play all 50 at once though.
Photo-JPEG is less efficient but has the advantage of working at any resolution (it also has a lower data rate at the same size as DV). Motion-JPEG is the same as Photo-JPEG, but uses two interlaced fields per frame.
I highly recommend avoiding anything with MPEG in the name if performance and image resolution are required.
chris clepper wrote:
On 11/5/05, patrick puredata@11h11.com wrote:
hi,
i was wondering about mac os X ? what is the best codec for mixing (blending, seeking) videos? quicktime for sure, but what codec and size: 720x480 DV or 640x480 with a codec like mpeg4, photojpeg? it's a g4 laptop, with 512 ram.... 50 videos, 2 seconds each.
I get at least 3 NTSC DV clips playing 30 fps at once on a 1 Ghz G4 laptop using the internal drive. A fourth might be possible using a Firewire drive. I hope you aren't trying to play all 50 at once though.
Photo-JPEG is less efficient but has the advantage of working at any resolution (it also has a lower data rate at the same size as DV). Motion-JPEG is the same as Photo-JPEG, but uses two interlaced fields per frame.
I highly recommend avoiding anything with MPEG in the name if performance and image resolution are required.
GEM-dev mailing list GEM-dev@iem.at http://lists.puredata.info/listinfo/gem-dev
hi chris, no no. i'm not trying to play 50 clips at the same time. but, i would like to be able to load a clip without visual glitch or freeze. is this possible?
also, i'm wondering about the correct size of a clip if i know the projection will be @ 800x600. should i crop my dv (720x480) to 640x480 to keep the ratio size. if yes, i will be forced to use a codec like photo jpeg right?
pat
Hi Patrick,
On 05-11-06, at 08:17, patrick wrote:
chris clepper wrote:
On 11/5/05, patrick puredata@11h11.com wrote:
hi,
i was wondering about mac os X ? what is the best codec for mixing (blending, seeking) videos? quicktime for sure, but what codec and size: 720x480 DV or 640x480 with a codec like mpeg4, photojpeg? it's a g4 laptop, with 512 ram.... 50 videos, 2 seconds each.
I get at least 3 NTSC DV clips playing 30 fps at once on a 1 Ghz G4 laptop using the internal drive. A fourth might be possible using a Firewire drive. I hope you aren't trying to play all 50 at once though.
Photo-JPEG is less efficient but has the advantage of working at any resolution (it also has a lower data rate at the same size as DV). Motion-JPEG is the same as Photo-JPEG, but uses two interlaced fields per frame.
I highly recommend avoiding anything with MPEG in the name if performance and image resolution are required.
GEM-dev mailing list GEM-dev@iem.at http://lists.puredata.info/listinfo/gem-dev
hi chris, no no. i'm not trying to play 50 clips at the same time. but, i would like to be able to load a clip without visual glitch or freeze. is this possible?
also, i'm wondering about the correct size of a clip if i know the projection will be @ 800x600. should i crop my dv (720x480) to 640x480 to keep the ratio size. if yes, i will be forced to use a codec like photo jpeg right?
No you should not crop your DV. DV are 720x480 because they have non-square pixels. Their size ratio is still 4:3. DV is the best choice but you can only get full resolution (720x480). If you need other resolutions, use mjpeg or photo-jpeg. And it's quicker to load one big file that contain all your 50 files and just seek in it, if your setup permit this. Unfortunately it's not easy in PD-Gem to seek in quictime file and have a smooth playback because to have a smooth playback you need to use "auto" and when you use "auto" the seeking function doesn't work very well, at least in the version I was using (Gem 0.9 I think).
Good luck
Etienne
pat
GEM-dev mailing list GEM-dev@iem.at http://lists.puredata.info/listinfo/gem-dev
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B. Bogart -
chris clepper -
Etienne Desautels -
IOhannes m zmoelnig -
patrick